ETIOLOGY 



51 



the animal body ; but in certain cases, especially in encysted 

 deposits in the lungs, the virus may remain active for a much 

 longer time. 



Baumgarten and Hell oppose the view that Schiitz's strep- 

 tococcus is specific, while Rust and Fiedler support it. Hell 

 maintains that with our present means of investigation, the 

 bacteria of contagious pleuro-pneumonia cannot be differen- 

 tiated from the pyogenic streptococci or from the strepta- 

 coccus of erysipelas In fact, Hell believes that the strepto- 

 coccus of Schiitz has a pathogenic effect in horses affected 

 with pleuro-pneumonia ; but as there is no positive proof of 

 its being specific, he maintains that we are justified in sup- 

 posing that this ubiquitous microorganism simply has an injuri- 

 ous influence on the course of .the disease, contributing to the 

 production of the secondary lesions. Hell further states that 

 protective inoculation with Schiitz's bacteria, which at first 

 promised good results, has not proven to be satisfactory. 

 Fiedler, on the other hand, has obtained the same bacteriolog- 

 ical results and has arrived at the same conclusion as Schiitz. 

 He also states that he has experimentally produced pleuro- 

 pneumonia in a horse b}' inoculation of cultivations of these 

 bacteria. 



Lignieres believes that his cocco-bacillus stands in an 

 etiological relation to this disease and that here, as in strangles, 

 the streptococcus is a secondary invader. This view has not 

 been confirmed. 



The writer made a bacteriological examination of the 

 organs from five cases of fatal contagious pneumonia of the 

 horse. In each case, the lungs were more or less hepatized, 

 but the other organs were nearly normal in appearance. 

 Without exception, a streptococcus appeared, usually in pure 

 culture, from the lungs. The inoculated media from the other 

 organs (liver, spleen, and kidney) remained clear. The strep- 

 tococci isolated from the different cases were identical in 

 their morphology, cultural manifestations and pathogenesis. 

 A microscopic study of the lungs from the different horses 

 showed streptococci singly, in pairs and occasionally in short 



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